1. Field of the Invention
The present invention relates to a label separator that separates labels from a carrier web and a label printer equipped with the label separator.
2. Description of the Related Art
FIG. 20 is a perspective view of an existing label printer 101. FIG. 21 is a perspective view of an existing label separator 120. FIG. 22 is a cross-sectional view illustrating the configuration of the existing label separator shown in FIG. 21.
Referring to FIG. 20, the label printer 101 includes a thermal head 103 mounted to an upper cover 106, and a platen roller 104 and a paper roll holder 105 mounted on a chassis 102.
The roller paper holder 105 holds a print medium in the form of a label web. The paper roll holder 105 includes two opposing support members for rotatably supporting the label web. The distance between the two opposing support members is adjustable depending on the width of the label web. The core about which the label web is wrapped is rotatably fitted to a boss on each support member of the holder, thereby loading the paper roll on the paper roll holder 105.
The upper cover 106 is pivotally supported on supports of the chassis 102. When the upper cover 106 is opened or closed relative to the label printer 101, the thermal head 103 moves into or out of engagement with the platen roller 104. The tip portion of the label web is led out through a gap between the thermal head 103 and the platen roller 104, and further outwardly from the chassis 102. The upper cover 106 is then closed with the label web sandwiched between the thermal head 103 and the upper cover 106. The rotation of the platen roller 104 causes the label web to advance, and the thermal head 103 prints on the label web under pressure.
A label web 110 includes a series of labels 112 affixed to a long belt-shaped carrier web 111, the labels being spaced by a predetermined distance. The label printer prints on the series of labels.
As shown in FIGS. 21 and 22, the label printer 101 includes a label separator 120 for separating the labels 112 from the carrier web 111.
This type of label separator 120 is disposed downstream of the thermal head 103 with respect to transport of the label web, and includes an edge member 107, a pressure roller 108, and a front cover 109. The edge member 107 abuts the label web 110 transported by the platen roller 104, causing the carrier web 111 to be kinked at a predetermined angle. The edge member 107 separates the label 112 from the carrier web 111, allowing only the carrier web 111 to advance to the gap between the pressure roller 108 and the platen roller 104. The pressure roller 108 is rotatably mounted on the front cover 104, and presses the carrier web 111 against the platen roller 104 under pressure, while being driven by the platen roller 3 in rotation.
The label web 110 is transported by the platen roller 104 past the edge member 107 after the label 112 is printed by the thermal head 103, and the label 112 is then separated from the carrier web 111 and is further transported to the outside of the apparatus through a label discharging path.
The label 112 is transported further in a substantially straight path while the carrier web 111 is bent by the edge member 107 and is then advanced to a pressing point where the carrier web 111 is pressed by the pressure roller 108 against the platen roller 104. The carrier web 111 is then transported along the label discharging path of the carrier web to the outside of the apparatus.
In this manner, the existing label separator operates to separate printed labels from the carrier web.
Japanese Patent Application Publication No. 2007-145527 discloses another type of label separator in which a drive roller is mounted to an openable-and-closable member pivotally mounted on the label printer and cooperates with a driven roller mounted to the label printer to hold the label web between the drive roller and driven roller, and the edge member causes the label to separate from the carrier web.
The above-described existing label separator suffers from the following drawbacks. The label web is first sandwiched between the platen roller and the thermal head, and then the leading end portion of the label web is passed by manually through a gap between the pressure roller and the platen roller, and the leading end portion is pulled by the operator through the discharging path located, for example, under the front cover. If the label web is pulled by tension smaller than necessary, the label web tends to have slack therein with the result that the edge member cannot engage the label web at a sufficient angle with the carrier web, failing to separate the labels reliably.